1. Field of the Invention
This invention relates to relief valves and more particularly to a collapsible pin relief valve trigger for releasing a valve flapper or piston on a relatively large diameter pressure fluid container in response to a predetermined pressure in the container acting on the valve trigger.
In the past, I have sucessfully produced collapsible pin relief valves utilizing Eulers Law acting on a pin for monitoring pressure in a conductor generating axial forces up to approximately 16,000 pounds (7200 kg) against the pin.
There is a need for a relief valve trigger to monitor relatively high fluid pressure in a container of relatively large diameter, for example, 5 feet 6 inches (1.70 m).
This invention solves this problem by providing a relief valve trigger mounted exteriorly of a container to be monitored and communicating with the fluid therein which releases a container closure member in response to fluid pressure above a predetermined value by the collapse of a collapsible pin.
2. Description of the Prior Art
The most pertinent prior patent is believed to be my U.S. Pat. No. 5,012,834 issued May 7, 1991 for FLUID PRESSURE FLARE RELIEF VALVE. This patent discloses a valve body connected with a fluid line in which the valve body is enlarged and provided with a lateral opening normally closed by a double wall valve head to form a valve head chamber laterally of a fluid passageway through the valve body. The fluid passageway contains a chamber having aligned bores in opposite walls normally closed by dual pistons secured to a piston rod projecting through the valve head chamber and through the closed end of a cylinder projecting into the valve head chamber and through the closed end of a cylinder projecting into the valve head chamber and slidably supporting a smaller diameter pilot piston secured to the piston rod. The outwardly projecting end of the piston rod supports one end of an excess fluid pressure collapsible pin supported at its other end by the end plate of a pin cage surrounding the collapsible pin and connected with the cylinder projecting out of the valve head chamber. A spring urged poppet valve admits upstream fluid pressure to the valve head chamber so that excess pressure above a predetermined value against the pilot piston and the piston remote from the valve head chamber unbalances the pistons, collapsing the pin to release the excess pressure through the passageway downstream outlet.
This invention is distinctive over this patent by providing a relief valve trigger mounted exteriorly of a vessel containing fluid to be monitored which features a diaphragm releasably connected with a closure member for the fluid being monitored in which excess fluid pressure moves the diaphragm to a closure member released open position and releasing the fluid pressure in the chamber being monitored. Other distinct differences are the moveable pressure containing member is held rigidly in a compressed seal contact until triggered to an open mode by a set upstream fluid pressure, the opening force to open is cushioned to limit the opening velocity of the moveable pressure containing member, and the weight of the moveable pressure containing member is compensated.